This application claims priority to application Ser. No. 1016786 filed in The Netherlands on Dec. 4, 2000 under the title xe2x80x9cSingle Control Tilt Drive Unit.xe2x80x9d
1. Field of the Invention
This invention relates to a monocommando tilt drive unit for a covering for an architectural opening, such as a venetian blind.
2. Description of the Relevant Art
Monocommando drive units for operating venetian blinds are known. See, for example, UK patents 1 187 214 and 2 049 006. Typically such mechanisms have been adapted to tilt, as well as open and closexe2x80x94i.e., raise and lower (for horizontal blinds) or extend and retract (for vertical blinds)xe2x80x94a plurality of mutually interconnected slats of a blind by means of a single common control device.
A disadvantage of existing monocommando devices for horizontal or vertical blinds is that when opening and closing such blinds, their slats are virtually closed. For horizontal blinds, this results in the apertures in the slats, for the passage of the lift cords, rubbing against the slats as the lift cords move through the apertures and causing wear and tear to the lift cords which can eventually break them.
In accordance with this invention, a tilt drive unit (A,Axe2x80x2, Axe2x80x3) is provided for a covering for an architectural opening, such as a venetian blind (C,Cxe2x80x2,D), which tilt drive unit includes (with reference to FIGS. 1-5):
a roller (1,101,201) that has a circumferential track formation (5,105,205) on a radially outer surface thereof and is adapted to be rotatably driven; and
a movable tilt member (3,4,103,104,203,204) that is engaged by the circumferential track formation (5,105,205) on the roller (1,101,201) for sliding movement in the track formation and is operatively engaged with means (6,7,106,107,234,235) to tilt slats (B,Bxe2x80x2, Bxe2x80x3) of the covering (C,Cxe2x80x2,D);
wherein the track formation (5,105,205) has a free zone (12,112,212) and a tilt zone (13,113,213), whereby when the tilt member (3,4,103,104,203,204) is engaged by the free zone, the slats of the blind will be retained in an open position and whereby when the tilt member is engaged by the tilt zone, rotation of the roller (1,101,201) will cause the slats of the blind to be tilted to either of two opposite positions of tilt.
This tilt drive unit allows the slats of a venetian blind to be opened and closed, while the slats are open (thereby allowing the lift cords in a horizontal venetian blind to run freely through the apertures in the slats). This tilt drive unit is also considered easier to assemble and operate and less expensive to manufacture than other monocommando devices for venetian blinds.